Process of performing catalytic vapor phase reactions



April 15 1947- c. w. STRATFORD ETAL 2,418,857

PROCESS oF xFoRMINe'cATALYTIc VAPOR PHASE gEAcTIoNs April l5, 1947. c. w. sTRATFoRD ETAL 2,418,857

PROCESS OF PERFORMING CATALYTIC VAPOR PHASE REACTIONS l Filed Nov. I0, 1943 2 Sheets-Sheet =2 Hh. H

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4 WENEV- Patented Apr. 15, 1947 reactions perinluding reacy fe 'reaction or tepels but is H progssdwherein the oigjreacino are maintained i ef; lxanvlples of such version or crackingy 'Well as' hydrogen..

In processes ihriyolving catalytic chemical rac? UNITED, sTArEsmPnTEN-r ortica "iainsgssv l I HAgilS BEACTIGNS StratfgiLJ A'iAlt's'Iinler. and David s; tratfords Development Corporation, Kansas tMasavcorporation of Delaware l In contrast thereto therelis-hereiprovi'dedasysaf 'b ughtjinintimate con- 19 inerization, polymerl5 l instant `process may be `used. i f l tio s metals for. nietalsin' combination with other 2 cataly tslnill: q lreduiredjwh'ile in processes involving'- t'he conversion of f hydrocarbons natural ors'yntheticclay's, maybe 'used. The size of the eataiystywiui bfeseiectedgacqrding to the condiof the, ,ra`ctants, poro'sityfof 'the' particles and otherffactorsl'which willaffe'ct contact between the numana siidsin thegmixture.'

In brief, the lsalient features of novelty in the process fas applied' to" I catalytic cracking reside 30 primarily in imparting velocity to the mixture of gaseous reactants and .catalyst entirely independent ofthe energy supplied by the feed of said materialsto the reaction or regenerating steps. By

this independent control' over the velocity a more 35 homogeneous anduniform mixture of the particles of catalyst and reactants isV obtained than by relyingupon energy furnished -by pumps or re ductionof pressure of the feed.

Afurther feature of novelty is the control ob- 40 tained over the ratio of catalyst to reactants by recirculation., of unregenerated vcatalyst to the reaction step.y An additional feature is the establishment of separate cyclic zones, a reaction zone,

Where ahomogeneous mixture of catalyst and 45 fluidy reactants is created,V a regenerating zone Where, astream `.of contaminated catalyst and combustible or` oxidizing gas exists, and mainv taining uniformity and homogeneity in thesepaite 'zonesor cyclic streamsfby means of a posiro tirev mechanical V.rotor h or( impeller which maintains the suspended particles ofthe catalyst dis; persed throi'ighoutV the gaseous media'in which it isV suspendedf It'isknovvnthatheretofore the importance of 55 tions maintained including .thvelocity of travel 25 ture'jl'iave V always been "dependent upon-energy sipplifel through thefe'ed'to' threactor or regen;

eratorito"obtain'effectivecontact and A'oklispers'iomf 6.9

ca'rLYirrc tem and process injwhich"fthevelocityof the cir'- culating streams governs'thecompleteness 'ordispersion or extent ofcontact'of the fluid and solid' particles and 4this velocity is entirely independentfrf` of the, energy supplied through' the agencyof the feeds to the reactor or'reg'enerator.:A

Attempts have been fmad'e'tofcontrol components and insomeA cases' af" reduction: in

ratio was obtained by bleeding@ *a* portion# of ltlieiy :,w catalyst from the cycle] InsofariasV is knownfx'f however, no provision has ever-beenfvmadeifor's; increasing the ratio o'f the cata1yst'andlreactants== 1 above the ratio established bythe feed.

There are indications that particularly 'mths conversion o'f hydrocarbons, thatfeliminatioiifof 1. liquid particles inthe feed reducesto'a great'fex-l` f tent excessive and rapid carbon'formation contamination ofthe catalyst' particlesrf?" #7 I Y An'ac'curate control of the degree of contamination can be had by `recycling selected amounts"- of regenerated yand'unregeneratedi-catalyst.` It has been found that a certaindegree of catalyst fouling is in some instances advantageous.

Rapid circulation and intimate contact of the reactants and catalyst and even distribution of the catalyst throughout the stream of *reactants* or throughout the stream of regenerating gas' permits the use of optimum temperatures in the reactff.' and regenerator. vIn the conversion of hydrocarbons temperature Aconditions Vmaybe more accurately controlled due to uniformity of distribution of the catalyst and reactants'and the Y resultant product more definitely predicted;v Intimate contact and uniform' dispersion obtained l by energizing the streams of suspended catalystindependently of the feed in the reactor and re-V generator exposes considerably more catalytic surface to the reactants and combustion gases and eliminates dead spots in both stages.

vBy the present method the residence time of the catalyst and reactants in thel reaction stage is the same while in present commercial catalytic methods the replacement of the catalyst has never corresponded lor approximated the same` frequency as the change ofthe reactant; *Thel process affords catalyst'withinlthe reactor ina more uniform and? constant state of'activitythan in"v catalytic `methods 'Wherefastatic bedlorf "a movingbed are used; ObviouslytooL only ins'ys.. l

tems Where the Sidec-tm (ify the catalyst and' 1 the-'reactants is the vsame'canthe activity ofthe" l As fouling of theV catalyst'is greatly'reducedfbyi limiting its residenceltime inthe reactor, removalI Vof this contaminationby'oxidationllinl-thefre? generator morey easily 'effectedfandfatfconsid.

erabiyflo'wer 'temneraniresi eliminating to "igrat l the.. and of catalyst to reactants by the feedI rate ofthe-t extent the possibility of damage to the catalyst by excessive temperatures normally existing during regeneration or caused by localized overheating.

Further objects and advantages of the invention will be apparent during the course of the following description in whichI the process has been applied to the cracking of hydrocarbon oils in the presence of a finely divided solid catalytic material such as natural or synthetic clay,

In the accompanying drawings which form a part of the instant specification and are to be read in conjunction therewith,

Fig. 1 is a flow diagram of the process as applied to the cracking of hydrocarbon oils,

Fig. 2 is a sectional view of the vapor contacter and regenerator,

Fig. 3 is a. view taken along the line 3 3 in Fig. 2 in the direction of the arrows,

Fig. 4 is an enlarged detail of the impeller assembly.

As suggested heretofore the process will be described as applied to catalytic cracking but such disclosure is not to be read in a limiting sense since it is applicable as well to all types of catalytic chemical reactions in which fluids (gases orliquids) are contacted with a solid catalyst.

Referring to Fig. 1, which is a flow diagram of a catalytic cracking system, the hydrocarbons are fed to the system from any convenient source such as a storage tank shown at l0. The feed stock passes through pipe Il and is discharged by means of pump I2 into a heater diagrammatically shown at i3. In the heater the feed stock is raised to a vaporizing temperature after which it is discharged through a transfer line I4 into the bottom of a fractionating tower l5. In the tower liquid is separated from the vapor constituent, the former being .drawn off through pipe I6 and discharged by pump I1 through pipe i8 to storage or for treatment elsewhere. The vapor portion of the feed passes off from the top of the tower through line i9 and may be directed through pipe to a mist extractor 2|- By closing valve 22 and valve 23 and opening valve 24 in pipe 25, the mist extractor may be by-passed.

Vapors passing to the mist extractor are denuded of entraned liquid particles, the liquid passing out through draw-oft' line 26 regulated by valve 21 for recycling'through pipes 28 and I4 to the fractionating tower. The vapors discharged from the top of the mist extractor pass through line 29 to heater 39. The temperature of the vapors in heater 39 is raised the desired amount to put the vapors in condition for further processing. By-pass line 3| and suitable valves 32, 33 and 34 offer means for by-passing the heater if desired. From heater the hydrocarbon vapors are discharged through line 35 and are directed through a second mist extractor 36 which may be by-passed through line 31 by proper'manipulation of valves. Liquid separated in mist extractor 36 is withdrawn through pipe 38 and may be recycled by pump 39 through pipe 49 to transfer line I4 or diverted from the system through cooler 4I and pipe 42. It is contemplated that the hydrocarbon charged to the reactor may be in the liquid phase in cases when there is suicient heat available in the catalyst fed to the reactor to vaporize the charge.

'The vapors now conditioned by removal of entrained liquid particles and the heavier ends passv through pipe 43 to line 44 which charges them into the contactor reactor 45, This reactor is similar in construction to the contacter regenerator shown at 46 and detailed-in Fig. 2 of the drawings. The solid catalyst is supplied from a tank or bin 41 designated as new clay storage. This catalyst is withdrawn from storage 41 through pipe 48 and is passed through diagonal pipe 49 and mixed with the vapors in pipe 44.

- The mixture of vapors and catalyst ows into the vessel and is there reacted as hereinafter described in connection with the explanation of the contactor.

The reacted vapor catalyst mix is discharged from contacter 45 through pipe 59 through whichit passes to a separator 5I where the greater part of the solid material is separated from the vapor. An open steam connection 52 supplies steam to the separator for removing volatile hydrocarbons and purging the catalyst voids of hydrocarbon vapors. Catalyst removed from the vapor during the separating and stripping operation in 6I passes through pipe 53 to recycle clay storage 64. This storage tank has a return connection 65 through which used or unregenerated clay can be recycled through pipes 49 and 44 to the reactor or by vclosing valve 56 and opening valve 51 in pipe 58 the used clay is diverted to regenerator 46 through pipe 59. A connection 69 into the top of the spent clay storage tank 54 also communicates with the bottom of reactor 45 and may be used to exhaust catalyst from the reactor when the plant is shut down by introduction of gas or steam through pipe 6I.

Following the vapor travel from the top of separator y5I the vapors pass through pipe 62 either directly to fractionation 63 through pipe 64 or by closing valve 65 and opening valve 56 ir: line 61, the vapors are passed through precipitator 68 where additional catalyst nes are extracted. This additional catalyst in a relatively ne state is returned from precipitator 63 through -pipe 69 to the used catalyst storage 54. Vapors from the precipitator pass through pipe 19 to fractionation 63 through pipe 64. By-pass lines 1I and 12 controlled by suitable valves offer opportunity for by-passing the precipitator and diverting the vapors through heat exchange 13 prior to directing them to fractionation. In the fractionating equipment diagrammatically shown at 63 there is separated a fuel oil or recycle stream awhich passes. oil through pipe 14, av gasoline stream diverted through pipe 15 and unlquied gas through pipe 1B. A part or all of the liquid bottoms separated out during fractionation containing catalyst nes may be recycled through pipe 11 to be introduced into the reactor through pipe44. By closing valve 18 and opening valve 19 this recycle liquid or slurry containing catalyst iines not previously separated are recycled to separator 5I through pipes 11, 80 and 59,

Referring now to the catalyst regeneration used catalyst from storage 54 which is at substantially reactor temperature flows through pipes 55, 58 and 59- to regenerator 46. Air to burn off or consume by oxidation the accumulatedcarbon particles fouling the hot catalyst is introduced with the clay to the regenerator through pipe 59. Air supplied through pipe 6I is charged by compressor 82 to heater 83 through pipe 84. After heating the air is discharged through pipe B5 and is introduced to the regenerator through connecting pipe 59 for starting regenerator. The heater B3 may be by-passed through line 86 by manipulation of the valves 81, 88 and 89 during normal operation.

In the -regenerator catalyst contamination is removed to the extent desired while circulating the stream of gas and catalyst through the vessel.

storage tank 93. Steam may be introduced to. separator 9| through pipe 94 to assist in the catalyst separation and purge the catalyst voids oi' combustion gases and air. Regenerated catalyst accumulated in storage 93 may be drawn of! through pipe 95 and combined with fresh catalyst or with used catalyst which is being charged to thereactor through pipes 39 and M. Valves in the draw-olf lines from the separate catalyst storage tanks are used to control the amount of the dierent types of catalyst which is recycled. To exhaust catalyst from the regenerator when the system is notin operation air under' pressure circulation tube in the shellof the contacter, as

is supplied through pipe 96 and the catalyst conducted as a suspensoid in the air media through pipe Sl into the top of storage tank 93. Each of the clay storage tanks dl, 53 and 93 has vent' lines 98. New clay storage tank 01 has a supply pipe through which fresh clay is added.

The ue gas relieved of the greater part of regenerated catalyst passes from. separator 9| through pipes |0| and |02 to a lprecipitator |03 in which additional fines are removed. The ue gas passes from the top of the lprecipitator through pipe |03 while the nes separated in precipitator |03 are drawn off through pipe |05. to be returnedthrough line |06 to storage 93 or diverted from the system through pipe |01. y

yBefore extracting the regenerated catalyst in separator 9| and the nes in precipitator |03 the ilue gas catalyst mixture may be diverted through waste heat equipment designated diagrammatically at |08 and |09.

To clean the equipment either before or after operation steam may be introduced through pipes |||l. Recycle gas may be introduced into-the reactor and fuel gas to the regenerator for direct ring through lines ||0. In order to remove accumulated material in both the reactor.` and regenerator air blasts may be injected through pipes Connected to the regenerator i6 by pipes ||2 and ||3 is a heat exchanger or boiler diagramm'atically shown at 99. This boiler may be used as a temperature control device for the combustible gas`catalyst mixture passing through the regenerator and may be built integral therewith instead of as a separate unit as shown. Fluid is supplied to the boiler through pipe ||4 and discharged therefrom through pipe |5. A drawoi pipe `||6 with a suitable valve is connected into the heat exchanger to divert catalyst should it be desired todo so.

A'diversion pipe I1 is connected into the oil catalyst slurry line 10 for removing the slurry from the system instead of recirculating it to the reactor.

The reactor 45 and regenerator 46 are similar' vstandards for the device.

well as the impeller and all related parts which in any way are associated with the fluid flow, are

`highly streamlined and designed to reduce inso far as possible friction, concentration ofthe heavier solid particles or eddying of the mixture.

The shell I8, the impeller head I9, and lower head |20 are held together by tie rods |2|.4 Supports partially shown at |22 are arranged around the flange. of the impeller` head and serve as .Above the impeller head are motor supports |23 .which carry the motor enclosed within a casing |24. Motor-shaft |25 is connected to the impeller shaft -|20 by coupling |27. An enclosure |28 surrounding the Ishaft is flanged at the top and has a cover |29. Within this enclosure is a seal |30 which extends along the shaft preventing egress of the mixture fromthe shell. To cool and lubricate the seal circulating oil is supplied through pipe |3| and discharged through pipe |32. Oil is suppliedhub is a 'stationary member |36 which is fared to reduce to a minimum the resistance 4presented by the hub and shaft Aof the impeller. Supporting the member |36 within the tube are vcurved stationary vanes |31 which divert the direction of flow of the stream slightly in order that it enters the impeller with the least possible turbulence and in order to obtain the maximum driving effect of the rotating blades.

In the annular passageway formed in the impeller head around the upper end of the circulation tube is the upper splitter |38 which con-f lsists of a series of circular trough shaped mems bers telescopically arranged but spaced apart by support members |39. A single splitter member |60 is positioned in the annular passageway formed in the lower head of the contacter where the gas catalyst mixture passes around the end of the circulation tube. The functions of these splitter members is t0 divide the stream and prevent concentration of the heavier solid particles during reversal of the flow of the stream and to reduce turbulence at the turns. It also reduces abrasion caused by turbulence.

The material tobe mixed which in the reactor includes catalyst and reactant gases and in the regenerator catalyst and oxidizing gases are introduced at the bottom through a pipe designatedvby the numerals 44' and 53 to correspond to like numerals on the flow diagram in Fig. 1. Likewise the catalyst gas mixture, discharged from thevcontactor flows out through the horizontallpipe tapped into the impellerhead and designated by numbers 50 and 90 to correspond to the discharge lines from the reactor and regenerator in Fig. 1. To clean the shell and reactor an-air blast maybe introduced through pipes diametrically positioned inthe lower part of the shell numbered In operation the mixture of catalyst and gas introduced at the bottom of the shell is drawn Below the impeller and.

by the impeller up through the circulation tube |34 in a linear flow which is' rapidly accelerated at the impeller and discharged through the passageway formed in the impeller head where the direction of ilow is reversed and the mixture directed downwardly through the annular space.

between the circulation tube and the shell. Near the top and bottom of the shell and positioned radially in the annular space between'the circulation tube and shell are a plurality of straightening vanes HI which convert spiraling or turbulence in the flowingstream to linear movement.

By means of this device a thorough, complete and uniform dispersion of the catalyst through the gaseous medium with which it is circulated is obtained. Considerably more catalyst can be suspended in the gaseous medium by a positive independently driven impelllng device than where energy to produce the mixture is furnished through the agency of the feed itself. Thus, there is offered considerably more surface to the reactants or combustible gas than is possible with fixed bed, or moving bed. V

Particle size of the catalyst used will depend upon its weight and the velocity of the carrier medium, it being essential that conditions prevail in both the reacting and regenerating steps to assure complete mixing and uniform dispersion in order that a maximum surface of catalyst be exposed to the reactants and the greatest possible opportunity for elimination of fouling from the catalyst surface.

Heretofore mixing of catalyst with the reactants or regenerating gas was accomplished by passing the fluids through a static bed, counterflowing them with a moving bed or by contact with what is termed as a fluid mass of catalyst. This latter contact method employed or made application of the gas lift principle in which a downfiowing stream of high solids density is balanced with an upiiowing streamof gas of low solids density. This .method commonly known as the fluid catalyst system of contact is subject to the disadvantages and short-comings of the static and moving bed method to perhaps a lesser degree insofar as availability of catalyst surface is concerned. Channelling, accessibility and availability of catalyst surface in the reactor and regenerator are in all methods dependent upon and functions of the solids feed rate, composition, particle size and vapor or gas velocity produced by the feed.

Purposely no mention has been made of the operating yconditions of the catalytic cracking system described including character of the charging stock, temperature and pressure existing in the reactor, regenerator and separating stages, type of catalyst used or particle size of catalyst employed. Likewise, little or no importance has been given to the variety of different types of commercial processes to which the A 8 reducing capital, cost of equipment and operating expenses.

It 'is vcontemplated that multiple reactors may be used with a single regenerator or multiple .regenerators with multiple reactors while maintaining independent control in each reactor of the catalyst reactant ratios and the catalyst conditions.

As many possible embodiments may be made of the invention Without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

From the foregoing it will be seen that our invention is one well adapted to attain all of the ends and objects set forth, together with other advantages which are obvious and .which are inherent tothe process and apparatus described.

. Having thus described our invention, we claim:

1. A process of reacting gaseous materials in the presence of a solid catalyst wherein a cyclic i'low of the reactants and catalyst is maintained in the reaction step, said cyclic flow including upflowing and downowing columns having a common axis, the improvement which resides in imparting .mechanical rotative energy in the upper portion of the upfiowing column whereby lineal flow of the reactants and catalyst is accelerated in the separate columns.

2. In a process of reconditioning solid catalytic material in the lpresence of a gaseous medium` CHARLES W. STRATFORD.

JOE A, ALTSHULER.

DAVID H. PUTNEY.

REFERENCES CITED The following references are of record in the le of this patent:

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Reeves July 25, 1944 

